67 lines
2.2 KiB
Markdown
67 lines
2.2 KiB
Markdown
---
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layout: default
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title: Wildcard
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parent: Term-level queries
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grand_parent: Query DSL
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nav_order: 100
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---
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# Wildcard query
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Use wildcard queries to search for terms that match a wildcard pattern. Wildcard queries support the following operators.
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Operator | Description
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:--- | :---
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`*` | Matches zero or more characters.
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`?` | Matches any single character.
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To search for terms that start with `H` and end with `Y`, use the following request:
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```json
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GET shakespeare/_search
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{
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"query": {
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"wildcard": {
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"speaker": {
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"value": "H*Y"
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}
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}
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}
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}
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```
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{% include copy-curl.html %}
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If you change `*` to `?`, you get no matches because `?` refers to a single character.
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Wildcard queries tend to be slow because they need to iterate over a lot of terms. Avoid placing wildcard characters at the beginning of a query because it could be a very expensive operation in terms of both resources and time.
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## Parameters
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The query accepts the name of the field (`<field>`) as a top-level parameter:
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```json
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GET _search
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{
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"query": {
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"wildcard": {
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"<field>": {
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"value": "patt*rn",
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...
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}
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}
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}
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}
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```
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{% include copy-curl.html %}
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The `<field>` accepts the following parameters. All parameters except `value` are optional.
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Parameter | Data type | Description
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:--- | :--- | :---
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`value` | String | The wildcard pattern used for matching terms in the field specified in `<field>`.
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`boost` | Floating-point | Boosts the query by the given multiplier. Useful for searches that contain more than one query. Values in the [0, 1) range decrease relevance, and values greater than 1 increase relevance. Default is `1`.
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`case_insensitive` | Boolean | If `true`, allows case-insensitive matching of the value with the indexed field values. Default is `false` (case sensitivity is determined by the field's mapping).
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`rewrite` | String | Determines how OpenSearch rewrites and scores multi-term queries. Valid values are `constant_score`, `scoring_boolean`, `constant_score_boolean`, `top_terms_N`, `top_terms_boost_N`, and `top_terms_blended_freqs_N`. Default is `constant_score`.
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If [`search.allow_expensive_queries`]({{site.url}}{{site.baseurl}}/query-dsl/index/#expensive-queries) is set to `false`, wildcard queries are not run.
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{: .important} |